Mental illness the largest contributor to disability worldwide

Mental illness is the largest contributor to disability, according to a report card on the world's health, The Global Burden of Disease 2010 (GBD 2010). The seven papers and two commentaries that make up the report will be published in The Lancet this week. 

GBD 2010 is a collaborative project led by the Institute for Health Metrics and Evaluation at the University of Washington (UW) in the US and involves 302 institutions across 50 countries. This is the first report since the inaugural study was published in the early 1990s.

Close to a quarter of the world's disability burden is attributed to mental and behavioural disorders combined (22.7 per cent). These include major depressive disorder, anxiety, Alzheimer's, schizophrenia and bipolar disease.

Major depressive disorder alone accounts for 8.1 per cent of the disability burden and is second only to low back pain. This compares with cardiovascular and circulatory diseases, which account for 2.8 per cent of the disability burden.

"This report looks at the total impact of disease over a person's life. So serious conditions like heart disease and cancer contribute relatively small amounts to the disability burden because they usually occur in later life," says UNSW Professor Philip Mitchell, who assisted in assessing the impact of bipolar disease around the world for the report.

"The mental illnesses present very commonly when people are in their 20s and 30s and they often reoccur, so the lifetime disability is greater," says Professor Mitchell, Head of Psychiatry at UNSW, who is based at the Black Dog Institute.

Other key findings relating to mental health:

• The burden of major depression and anxiety have each increased by 37 per cent in 20 years
• Alzheimer's disease has increased by 80 per cent
• Major depressive disorders account for 63 million years spent living with a disability (YLD)

Other contributions from UNSW experts include:

• UNSW Conjoint Professor Guy Marks contributed to the work on respiratory diseases. Pneumonia, tuberculosis, chronic obstructive pulmonary disease (or COPD, the occurrence of chronic bronchitis or emphysema) and lung cancer are major contributors to the global burden of disease and premature death. One of the key findings is that the disability-adjusted life years (DALYs) due to pneumonia and other lower respiratory infections has decreased by 44 per cent over the past 20 years. However, the burden of lung cancer has increased while COPD, asthma and tuberculosis have remained relatively unchanged.
• Professor Louisa Degenhardt of the National Drug and Alcohol Research Centre at UNSW co-chaired the Expert Group on Mental Disorders and Illicit Drug Use. The results will be published in detail next year, but illicit drugs have become a bigger contributor to the global burden of disease over the past 20 years (from 1990 to 2010).